Protecting Backyard Fruit from Frost

Delicate blossoms of fruit trees like this peach are susceptible to frost damage. Photo courtesy of Bethany A. O’Rear

As edible landscapes gain in popularity, many gardeners have opted to include fruiting trees, blueberries and even strawberries in their gardens. Nothing is better than walking outside and harvesting a piece of delicious fruit at the peak of freshness. However, upcoming cold snaps could cause major frost damage to our fruiting plants, especially since many varieties are either in partial or almost full bloom. Remember – no flowers equals no fruit! The extent of damage, and the preventative measure that should be taken, depend on how cold it actually gets.

Generally speaking, when it comes to fruit trees, most can withstand temperatures to 28 degrees. At this temperature, the tree may lose 10% of the blooms, which can actually be helpful rather than harmful. Basically the weather is thinning the fruit for you, saving you time and effort later in the growing season. However, if the temperature drops below 28 degrees, even just a few degrees, bloom death can be in the 90% range. For home gardeners, covering your tree is probably the best option for frost protection, but depending on the size of the tree, this option may not be a practical one. If covering is possible, be sure that the cover extends all the way to the ground, encasing the plant. Crossing your fingers and hoping for warmer days may be the next best thing.

Many blueberry varieties are currently full of blooms, which puts these plants in a very vulnerable spot. At 30 degrees, blueberry blossoms can be damaged to the point that pollination is impossible and totally killed at 29 degrees. If your blueberry plants are at a manageable size, covering the entire plant with old blankets, row covers or even plastic sheeting it a good way to protect the delicate blooms. Once again, be sure that the cover extends all the way to the ground, completely enveloping the plant. The goal in covering is to capture the radiant heat from the soil that would otherwise be lost to the night air. One consolation for blueberry lovers is that the plant does not open all of its blooms at one time. So, if one does lose some flowers to the cold, more flowers should open up over time.

Strawberry blossoms. Photo courtesy of Bethany A. O’Rear

Strawberry blossoms can be severely damaged or killed at 30 degrees and below, so protection is extremely important. Covering is an easy option for these plants, as they grow so low to the ground. Similar to blueberries, strawberries do not bloom all at one time, so any bloom death that occurs will be replaced with new blooms down the road.

A couple of closing thoughts – all covers must be removed from the plants as the temperature rises above freezing, and then reapplied when another frost or freeze is predicted. Be sure to keep a watch on the weather, as we are not out of the woods when it comes to subfreezing temperatures. I expect at least one or two more cold snaps before spring is here in all its glory!

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The Alabama Cooperative Extension System operates as the primary outreach organization for the land-grant functions of Alabama A&M and Auburn Universities and answers home-gardeners' questions each week on Birmingham Gardening Today.